You're forgetting two things about Todd. First, he didn't know the bad guys were all that bad, just that they were recruiting. Second, nobody gives a fuck if Todd gets redeemed. You know how he ended the first movie? By not making out with a girl. I'd say he did pretty alright for himself in the second.
Oh, it's coming down to personal preference now? It's no longer an awful film that is, by your estimation, garbage? Why the change of heart? Realize you don't have a leg to stand on here?
The truth of the matter is that it's a perfectly fine film. It has a few good action scenes, entertaining comedy, a few cool characters, and it's a fun comic book movie. To say the director did a bad job just shows how little you actually looked into the film, as I thought he did a fantastic job. Almost every shot basically looked like a moving comic book panel, which is very similar to what Zack Snyder did (or tried to do depending on who you ask) with 300, which was a really fresh take on comic book movies. Instead of trying to make a movie like The Wolverine or Man of Steel where it's a comic book character placed in a movie, Kick-Ass 2 is a comic book made into a movie.
Furthermore, the film (and probably the comic, though I can't attest to that at this time) is clearly a post modern satire of super hero and comic book tropes. It's a satire that certainly benefits from the tropes that it makes fun of, but the same can be said of Austin Powers or Blazing Saddles or any film that parodies a certain genre.
Basically it seems obvious to me that you were predisposed to dislike this film, and you wound up disliking this film. Instead of looking for the positives you looked for the negatives, and while you may have found plenty of them, you still missed the plethora of positives the film delivered.
And it did not tank because it finished 4th (and really, it tied for 3rd more than anything). You don't measure the financial success of a film by what place it's in, you measure it by how much money it made. It made $20 mil on a $28 mil budget. That's pretty good. It should be able to turn a profit after about a month in theaters.